Environmental Problems, Their Causes, and Sustainability 1

average temperature and precipitation due to globalair and water circulation (Figure 6-10).Figure 6-16 shows how scientists have divided theworld into 12 major biomes. They are terrestrial regionswith characteristic types of natural ecologicalcommunities adapted to the climate of each region.Study Figure 6-16 carefully and identify the type ofbiome you live in.By comparing Figure 6-16 with Figure 6-6, you cansee how the world’s major biomes vary with climate.Make this comparison for the area where you live. Figure4-10 (p. 62) shows major biomes in the UnitedStates as one moves through different climates alongthe 39th parallel.Average annual precipitation and temperature (aswell as soil type, Figure 4-27, p. 75) are the most importantfactors in producing tropical, temperate, or polardeserts, grasslands, and forests (Figure 6-17, p. 112).On maps such as the one in Figure 6-16, biomesare presented as having boundaries and being coveredwith the same general type of vegetation. In reality,biomes are not uniform. They consist of a mosaic ofpatches, with somewhat different biological communitiesbut with similarities unique to the biome. Thesepatches occur mostly because the resources plants andanimals need are not uniformly distributed. Go to anatural area in or near where you live and see if youcan find patches with different vegetation.Tropic ofCancerEquatorTropic ofCapricornArctic tundra (polar grasslands)Boreal forest (taiga), evergreen coniferousforest (e.g., montane coniferous forest)Temperate deciduous forestTemperate grasslandDry woodlands andshrublands (chaparral)DesertTropical rain forest,tropical evergreen forestTropical deciduous forestTropical scrub forestTropical savanna,thorn forestSemidesert,arid grasslandMountains(complex zonation)IceFigure 6-16 Natural capital: the earth’s major biomes—the main types of natural vegetation in different undisturbedland areas—result primarily from differences in climate. Each biome contains many ecosystems whosecommunities have adapted to differences in climate, soil, and other environmental factors. In reality, peoplehave removed or altered much of this natural vegetation in some areas for farming, livestock grazing, lumberand fuelwood, mining, and construction.http://biology.brookscole.com/miller14111